The study of 1,455 adults, aged 18-74, found those with the highest concentrations of bisphenol A (BPA) in their urine had 2 to 3 times the odds of cardiovascular disease, compared with those with the least amounts of the compound in their systems.

It also found an association between BPA and abnormal concentrations of liver enzymes.

"Higher urinary concentrations of BPA were associated with an increased prevalence of cardiovascular disease, type 2 diabetes, and liver-enzyme abnormalities," the authors wrote.

Lang and colleagues say this is the first study to track the prevalence of BPA in the human body, and other researchers need to see if they can replicate the findings.

No known mechanism

Australian environmental toxicologist Professor Michael Moore of the University of Queensland in Brisbane says the authors make a "robust argument" for pointing the finger at BPA.

"I think it's a great paper," he says. "It's going to stimulate a lot of debate."

But, he says, there is no known mechanism by which BPA can cause heart disease.

Moore says while there was a "stand out" association between BPA levels and cardiovascular disease, the real culprit could be some other factor that is present at the same time as BPA.

He says further research should be carried out into the possible mechanism by which BPA could cause the diseases mentioned in the study.

Epigenetics?

Environmental toxicologist Associate Professor Peter Dingle of Murdoch University in Perth thinks future studies should investigate the possibility that BPA could cause disease through an epigenetic mechanism.

Dingle says this is suggested by the fact that in the new study, BPA was associated with abnormal concentrations of three liver enzymes.

He says BPA could be interacting with the genes for these enzymes and changing their expression levels.

Similarly, BPA could be interacting with genes that play a role in heart disease, says Dingle.

He says epigenetics may also explain recent studies that link diabetes and obesity with high levels of the pesticides DDT and heptachlor.

Endocrine disruption

Concern about BPA has previously focused on its potential to disrupt endocrine systems.

According to Food Standards Australia and New Zealand some studies in laboratory animals suggest that low levels of BPA may have an effect on the reproductive system, but it says this is unlikely to be a problem in humans.

The agency says it is continuing to examine reviews of the chemical from other regulatory agencies around the world.

Earlier this year Canada became the first country to move towards reducing infant exposure to BPA, and announced their intention to ban the sale of baby bottles made with the chemical.

More than two million metric tonnes of BPA were produced worldwide in 2003, and demand for the compound has increased by between six and 10% each year since then, say the authors of the new study.